AU+IMG2VID Refresh Policy (legacy alias)

The KeyframeTimeline node decides when to refresh; IAMCCS_AUIMG2VID_RefreshPolicy (legacy alias for Ltx2HelperModules_RefreshPolicy) decides how. Given the planner's segment plan and the keyframe schedule, it works out which refresh strategy each segment uses and how strongly to lock the anchor frames - then hands the result to the ReanchorLatent node as a refresh_payload. It's the tunable middle layer of the anti-drift system.

The single most important input is segment_policy, with four choices:

• planner_driven (default) - let the upstream planner decide per segment.
• continuity_only - just trim/blend overlap, no heavy re-anchoring.
• reanchor_mix - blend continuity with re-anchoring.
• reanchor_only - force a full re-anchor every segment (heavy, but maximum identity lock).

Around that sit the two presets, continuity_preset and reanchor_preset (each offering the same menu: lossless_refresh_24fps, target_extension_ltx2, videoclip_audio_24fps, monologue_audio_24fps, the cut_bestofk_* variants, etc.). These preset different blend behaviors depending on whether the segment is being treated as a plain continuation or a refresh point.

Then the anchor strengths, which are the knobs that actually change the output:

• first_anchor_strength (0.35) - how hard the first frame of the reference locks the generation.
• last_anchor_strength (0.2) - same for the last frame.
• tail_refresh_strength (0.3) - how strongly the tail of the previous chunk seeds the next.
• reanchor_overlap_mode - how the anchor region blends (cut, linear_blend, ease_in_out, filmic_crossfade, perceptual_crossfade).

Higher strength = better identity, more "locked down" motion. This is where the tradeoff lives: crank everything to 1.0 and your character stays the same but the video barely moves; drop toward 0.05 and it moves freely but drifts.

The outputs are the verdict for this segment: apply_refresh (boolean - does this segment refresh at all?), segment_role (a string like the resolved role), the effective strengths (first_anchor_strength_effective, last_anchor_strength_effective), and the counts first_lock_slots, last_lock_slots, end_transition_slots that tell downstream how many frames are being locked/transitioned. Wire refresh_payload into the ReanchorLatent node and you're done.

Where it sits: planner → audio timeline → keyframe timeline → refresh policy → re-anchor latent → runtime bridge. It makes the most sense there, because the presets were tuned for that chain - use the custom preset and you're back to setting everything by hand, at which point you should ask whether you need the node at all.

Installing: part of IAMCCS/IAMCCS-nodes - ComfyUI Manager → search "IAMCCS", or cd ComfyUI/custom_nodes && git clone https://github.com/IAMCCS/IAMCCS-nodes.git, restart. No models, no extra deps; it's policy math.

The trap is over-anchoring. New users see drift, set every strength to 0.8, and wonder why the video looks like a slideshow. Start with the defaults, and only raise first_anchor_strength/last_anchor_strength when a specific identity keeps slipping - that's the targeted fix, and it's what these separate strength inputs exist for.